U.S. Patent No. 4,169,341 describes an automatic document collating and envelope stuffing machine comprising a main flow path employing a continuous conveying mechanism to an envelope stuffing station, in which one or more feeding stations deposit documents onto a platform associated with each feeding station. The documents in each platform are picked up seriatim by the conveying mechanism and subsequently stuffed into envelopes. The feeding stations are each in parallel with the main conveying mechanism, which operates continuously to pick up whatever documents are present on each feeder platform.
While this machine operates satisfactorily for its intended purpose, it does have certain inadequacies which limit its flexibility and speed. For example, the speed is determined solely by the main conveying mechanism, which proceeds at the same velocity even though documents are not present on the platforms. Moreover, it is difficult to keep track of the collation contents from station to station. Still further, it is difficult, if not impossible, to employ a single address document with coding to indicate the collation contents which can control each of the feeding stations in turn.
Particularly, it is difficult to establish a communication protocol between modules in a modular insertion system which will permit maximum speed of operation while not restricting the manner in which modules inter-communicate. This is an important aspect for features such as queuing, pass collations, rejecting erroneous collations, passing error messages recognizing and adding new modules without the requirements of changing switches or re-programming memory, and multi-language capability for non-English language countries.